The manufacture and sale of portable communication devices, such as portable radiotelephones, has become a competitive business. To succeed, portable communication device providers must continually work to not only meet, but exceed, consumer demands. In doing so, portable communication device providers have improved the user interface of the portable communication device. One way of improving the user interface is by adding a touch sensitive input device, such as a touch screen or touch pad, to the user interface. Actuation of the touch sensitive input device allows a user to control operation of a portable communication device via finger tip touching or handwriting. One type of portable communication device that is known to incorporate a touch sensitive input device is a "smartphone." The smartphone is a single portable device in which radiotelephone functionality and personal computer (PC) or personal digital assistant (PDA) functionality are integrated. An example of a smartphone is shown and described in U.S. Pat. No. 5,715,524 to Jambhekar et al., entitled "Radio Communication Device With Movable Housing Element Control" issued on Feb. 3, 1998 and assigned to Motorola, Inc., the assignee of the present application.
Incorporating a touch sensitive input device into a user interface is problematic. Conventional user interfaces of portable radiotelephones, which include a speaker, a display, a keypad and a microphone, are arranged wholly on one side of the portable radiotelephone. It is desired to put the touch sensitive input device on the same side of the portable radiotelephone as the display because at least some actuations to the touch sensitive input device are replicated or tracked on the display. However, when the touch sensitive input device is carried on the same side of the portable radiotelephone as the speaker and microphone, the touch sensitive input device becomes susceptible to inadvertent actuations by a user's head while the user is listening at the speaker and/or speaking into the microphone.
Therefore, what is needed is a new way to control the user interface of a portable communication device such that, for example, a touch sensitive input device employed in the user interface is not inadvertently actuated while the portable communication device is positioned against the user's head.